Proxy Address Resolution Protocol (Proxy ARP) must not be enabled on the system.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-22415	GEN003608	SV-37624r1_rule	ECSC-1	Medium

Description
Proxy ARP allows a system to respond to ARP requests on one interface on behalf of hosts connected to another interface. If this function is enabled when not required, addressing information may be leaked between the attached network segments.

STIG	Date
Red Hat Enterprise Linux 5 Security Technical Implementation Guide	2017-03-01

Details

Check Text ( C-36823r1_chk )
Verify the system does not use proxy ARP. # grep [01] /proc/sys/net/ipv4/conf/*/proxy_arp|egrep "default|all" If all of the resulting lines do not end with "0", this is a finding.

Fix Text (F-31661r1_fix)
Configure the system to not use proxy ARP. Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.proxy_arp=0" and "net.ipv4.conf.default.proxy_arp=0". # sysctl -p